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Occurrence, phenotypic and genotypic characterization of strains of Corynebacterium pseudotuberculosis and Mycobacterium spp. isolated from lymph nodes of sheep with and without lymphadenitis

Grant number: 11/03120-1
Support type:Scholarships in Brazil - Master
Effective date (Start): August 01, 2011
Effective date (End): July 31, 2013
Field of knowledge:Agronomical Sciences - Veterinary Medicine
Principal Investigator:Marcio Garcia Ribeiro
Grantee:Thiago de Oliveira Zamprogna
Home Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

With the intensification of sheep production certain health problems has become alarming in the creation of the species. Among these, caseous lymphadenitis figure among the major diseases that affect sheep flocks worldwide (RADOSTITS et al., 2007). This disease causes significant economic losses in farms, resulting from the depreciation of the skin and wool, fall in the production of milk and meat, discarding of early animals and carcasses as well as the occasional death of animals (Williamson, 2001; PUGH, 2005). The caseous lymphadenitis is caused by the bacterium Corynebacterium pseudotuberculosis (C. pseudotuberculosis). The disease is characterized by abscess formation, particularly in superficial lymph nodes, such as the submandibular, pre-scapular, pre-femoral, popliteal and supramammary. However, it may also occur in lymph nodes and visceral in various organs, causing pneumonia, lymphadenitis (mesenteric, mediastinal, pre-hepatic), pyelonephritis, hepatitis, abscesses, soft tissue or other organs (RADOSTITS et al., 2007, Riet-Correa, 2001). The diagnosis of lymphadenitis is the most widely used microbiological isolation of the agent in specific media for their growth. The caseous lymphadenitis is considered an occupational zoonosis, affecting professionals engaged in the creation of the species. Treatment relies on antibiotics, however the drug is often ineffective due to the characteristic of intracellular bacteria. Tuberculosis caused by mycobacteria are also observed in sheep and characterized as alarming disease in relation to aspects of public health and animal health. However, historically, is recognized as a low prevalence in the herd sheep (RADOSTITS et al., 2007). The sheep tuberculosis is usually caused by Mycobacterium bovis, probably by creating consortiums or proximity between breeding cattle and sheep. The most common form of infection is by respiratory secretions, followed by ingestion of contaminated food, milk, vaginal discharges and also containing pus drained from abscesses (Pugh, 2005; RADOSTITS et al., 2007). The clinical signs of sheep tuberculosis are progressive weight loss, weakness, mild cough, breathing difficulty (Pugh, 2005; Smith, 2006). In severe cases, animals develop frameworks for hyperthermia, lethargy, pneumonia, dyspnea, and cachexia. Lymphadenopathy is common in tuberculosis, which may have been a localized or disseminated (Corrêa and Corrêa, 1992; Pugh, 2005; Smith, 2006; RADISTITIS et al. 2007) The diagnosis is based on microbiological culture, smear, PCR and more recently, experimental studies in Brazil have sought to validate tuberculin in small ruminants (Silva 2004, Silva et. al. 2006; Cyrille, 2006). (AU)